Speaker coil winding

[anchor]

I hope this is the right place to put this. I figure winding magnet wire is winding magnet wire so there shouldn't be much difference skill wise. Is it worth it to repair speaker coils?

Note: This thread was originally posted in the 'Tools and Coil Winding Gear' sub-forum of the 'Pickup Makers' forum.

[Leo_Gnardo]

I would expect, with the need to keep the coil & former perfectly circular, and the coil firmly glued in place, the skill set is much more demanding. And that's with round wire. How about winding JBL-style, flat wire, edge-on? Yikes! But - somebody's doing it somewhere, recone kits are being made & that's proof enough. I'm looking forward to what our pickup winding brain trust has to say.

[anchor]

How often does the brain trust check in?

[nosaj]

How often does the brain trust check in?

Why don't you try it and report back?
How much does a new speaker cost vs what you have to buy to repair one speaker and learn how to do it.
Do the math.
nosaj

[anchor]

At this stage of my understanding, I don't think it would be worth it for me. I've never worked with magnet wire. I probably don't have the tools and materials to make it worthwhile. That may not be the case for people already familiar with winding. It's why I posted here. Are you a member of the brain trust?

[big_teee]

How about this.
English not great, but the pictures are good.

[J M Fahey]

I hope this is the right place to put this. I figure winding magnet wire is winding magnet wire so there shouldn't be much difference skill wise. Is it worth it to repair speaker coils?

It can be done, but there´s some important differences.

FWIW I do wind my own voice coils, but I reserve that for custom jobs, such as cloning old Jensen voice coils, using old style synthetic enamelled wire, wound on paper formers, and glued with solvent based Nitro adhesives.

For bulk production speakers, I pay around $1 for a Chinese ready to use round copper on kapton former one, glued with high temperature epoxy and with leads precut and pretinned ... why worry?
You can get those in the usual sizes for $2 to $5 from Ted Weber, as well as suitable cones, suspensions, and everything else.

The few times where I was forced to rewind a voice coil still attached to the cone was wehere it was irreplaceable and removing voice coil (which to boot was odd sized) would destroy it, so ....
And it´s not a job for the faint hearted.

You also need to have a lathe available, better if on the same premises, because you need to make an exact size core to hold former (which is weak and flexible, paper thin) in the proper position against wire pressure , which is high because you want it tight.

A big difference with pickup winding is that these can be (and usually are) scatter wound, with one turn mounting on others not a big deal, while voice coils are two perfect layers, period, with each turn perfectly parallel and touching those on its sides.

And wire must be glued , of course, since it´s designed to vibrate back and forth, and push/pull a load 20 to 40 times larger than its own weight.

Car engines and most machines are *designed* to be disassembled and reassembled, that´s why they use bolts, pins, clamps, click together, etc. so you can half disassemble a car engine, take 200 parts out, replace some component deep inside and reassemble using all of the old parts.

Speakers on the contrary, and because of extreme weight and space considerations, are *glued* together, and are made of weak paper , cloth, foam, etc. so standard speaker repair procedure is to grab an X Acto knife, cut everything away (and junk it) , scratch old glue and reassemble with all new parts, except magnet and frame.

[anchor]

Thanks for the helpful posts. It looks like the choice of adhesives and glues are critical here. Where do you guys source yours? In my case, I have an 8" driver that froze. I considered using some de-oxit in the coil gap but that would leave the residue in there. Looking further, the ohm value is still in spec so the coil is probably not damaged. How would you guys approach this repair?

[J M Fahey]

Search any Industrial Epoxy supplier.
I use Araldit but can´t tell you the original name since my supplier buys the 55 gallon drums and repacks it into 250 gram and 1 kilo cans, with his own brand.
But it´s the one which is thick as honey at room temperature, mixed about 1:1 which makes measurement easier, one component is honey yellowish transparent, the other is whitish translucid, and takes some 6 to 8 hours to cure at room temperatuire.
It cures faster at higher temperatute, say 15 minutes at 100C and you must not go over 120C or it bubbles.
Any knowledgeable supplier willl find it with that data (which is pretty common) or give you another brand equivalent.
Toluene you get in small amounts (it´s a controlled substance) from your friendly Industrial Chemist,.
Enamelled wire from usual suppliers, with the caveat it **MUST** be the high temperature enamel type, Class F or H or better , guaranteed 160 or 180C operation, typically used to rewind electric motors.
The currently popular "self soldering" type, with atoms thin enamel which evaporates at low temperatures has no place inside a speaker.
The polished metal cores such as shown in the (very accurate) video are custom made on a lathe.
I suggest using small stiff brushes to apply epoxy instead of fingertip, I am half expecting the video guy to grow a tumor there, not kidding, uncured epoxy is very aggressive, as well as Toluene (and the impurities it carries which are left behind under your skin).

[nosaj]

Thanks for the helpful posts. It looks like the choice of adhesives and glues are critical here. Where do you guys source yours? In my case, I have an 8" driver that froze. I considered using some de-oxit in the coil gap but that would leave the residue in there. Looking further, the ohm value is still in spec so the coil is probably not damaged. How would you guys approach this repair?

What driver is it? If it's nothing special just replace it and be done with it. Hate to think your asking all this for a cheap chinese speaker.

nosaj

[galaxiex]

What driver is it? If it's nothing special just replace it and be done with it. Hate to think your asking all this for a cheap chinese speaker.

nosaj

Jeez, lighten up.

I do stuff like this all the time with cheap, junk, crap stuff that is broken or non functional.

I got nuttin to lose and I find out how stuff is put together, and how it works.

If I'm successful in the "repair"... then great! plus I learned something.

If I'm not successful then... no big loss, it was broken anyway...
BUT, I still LEARNED something, and may be better prepared to tackle working on something of value.

[Chuck H]

Jeez, lighten up.

I do stuff like this all the time with cheap, junk, crap stuff that is broken or non functional.

I got nuttin to lose and I find out how stuff is put together, and how it works.

If I'm successful in the "repair"... then great! plus I learned something.

If I'm not successful then... no big loss, it was broken anyway...
BUT, I still LEARNED something, and may be better prepared to tackle working on something of value.

He has a reason

[anchor]

I don't know that it is special but it seems well made. There is only a cryptic stamp of 220B. The magnet is ~135mm diameter and very strong. The basket structure is very rigid, it has tarred cloth, accordian surrounds, etc. It weighs 5 kilo. I don't think I could get similar quality for less than 100. I didn't pay for it so I don't know its origin. To get all the chemicals required will cost me ~60. A cheap replacement coil that fits might tempt me to try the repair. I'm still on the fence about it.

[big_teee]

Let's hope he winds it.
I would like to see what he comes up with.
Of Course we need documented play by play & pictures, along the way!
GL,
T

[nosaj]

I don't know that it is special but it seems well made. There is only a cryptic stamp of 220B. The magnet is ~135mm diameter and very strong. The basket structure is very rigid, it has tarred cloth, accordian surrounds, etc. It weighs 5 kilo. I don't think I could get similar quality for less than 100. I didn't pay for it so I don't know its origin. To get all the chemicals required will cost me ~60. A cheap replacement coil that fits might tempt me to try the repair. I'm still on the fence about it.

Where is your location, someone could suggest something close to you since your not in the US. Show us a picture, what did it come out of.
nosaj